Die cast system for forming a component usable in a gas turbine engine

ABSTRACT

A die cast system having an inner liner insert that enables the configuration of a component produced by the system to be easily changed by changing the inner liner insert without having to rework the die housing is disclosed. Because the inner liner insert only need be removed and replaced to change the configuration of an outer surface of a component produced by the system, the cost savings is significant in contrast with conventional systems in which the die would have to be reworked.

FIELD OF THE INVENTION

This invention is directed generally to die cast systems, and moreparticularly to manufacturing methods for turbine airfoils usable inturbine engines.

BACKGROUND

Turbine blade airfoils typically have internal cooling systems formedfrom a plurality of cooling channels, as shown in FIGS. 2 and 3. To formthese cooling channels inside of a blade, a casting mold is often usedand includes an internal ceramic core and external ceramic shell. Theceramic core, as shown in FIG. 1, is manufactured to include detailfeatures on the core die surface in order to form efficient coolingdevices inside the blade casting. The core dies typically used to formcores are most often formed from hard steel, which are expensive tomanufacture. The core die surfaces are typically in direct contact withthe ceramic core material during the high pressure injection process.The core die will wear out after sufficient injections and lead tonon-conforming casting. To maintain accurate casting dimensions, thecore die needs to be reworked or replaced when a core die becomes worn,which is an expensive endeavor. Even a small improvement on an internalsurface requires that a completely new die be made. Thus, a need existsfor a more robust, less expensive system.

SUMMARY OF THE INVENTION

A die cast system having an inner liner insert that enables theconfiguration of a component produced by the system to be easily changedby changing the inner liner insert without having to rework the diehousing is disclosed. Because the inner liner insert only need beremoved and replaced to change the configuration of an outer surface ofa component produced by the system, the cost savings is significant incontrast with conventional systems in which the die would have to bereworked. The die cast system may also include an inner liner formedfrom first and second end sub-inner liners, whereby the first endsub-inner liner may be from a first material that is less compliant thana material forming the second end sub-inner liner enabling moreintricate cooling systems to be created by the second end sub-innerliner that is formed from a more compliant material.

In at least one embodiment, the die cast system may include a diehousing having one or more inner chambers forming an insert receivingchamber and one or more inner liners positioned within the insertreceiving chamber of the inner chamber of the die housing. The innerliner may have an inner surface defining boundaries useful to form aninner surface of a turbine component, whereby the inner liner may beformed via a selective laser melting process. The inner liner may beformed from a first side sub-inner liner forming a first side of theturbine component and a second side sub-inner liner forming a secondside of the turbine component. The first side sub-inner liner may forman outer wall of a suction side of an airfoil usable in a gas turbineengine and may include at least one cavity on an inner side of the outerwall that is configured to form at least a portion of an internalairfoil cooling system. The second side sub-inner liner may form anouter wall of a pressure side of an airfoil usable in a gas turbineengine and may include one or more cavities on an inner side of theouter wall that is configured to form at least a portion of an internalairfoil cooling system.

In at least one embodiment, the inner liner may be formed from anon-ceramic, flexible material. The inner liner may be formed from adifferent material than the die housing. The die housing may be formedfrom a first sub-die housing and a second sub-die housing having amateable interface positioned therebetween such that the first andsecond sub-die housings are mateable at the mateable interface.

In another embodiment, the inner liner may be formed from a first endsub-inner liner forming a first end of the turbine component and asecond end sub-inner liner forming a second end of the turbinecomponent. The first end sub-inner liner may be formed from a firstmaterial that is less compliant than a material forming the second endsub-inner liner. The second end sub-inner liner being more compliant maybe used to form intricate aspects to the internal cooling system. Thefirst end sub-inner liner may be configured to form a leading edge of anairfoil usable in a turbine engine and second end sub-inner liner isconfigured to form a trailing edge of the airfoil usable in the turbineengine.

In at least one embodiment, the first end sub-inner liner may be formedfrom a first end, first side sub-inner liner and a first end, secondside sub-inner liner. The first end, first side sub-inner liner may forma suction side outer wall of an upstream portion of a suction side of anairfoil usable in a gas turbine engine and may include one or morecavities on an inner side of the suction side outer wall that isconfigured to form at least a portion of an internal airfoil coolingsystem. The first end, second side sub-inner liner may form a pressureside outer wall of a pressure side of the upstream portion of an airfoilusable in a gas turbine engine and may include one or more cavities onan inner side of the pressure side outer wall that is configured to format least a portion of an internal airfoil cooling system.

The second end sub-inner liner may be formed from a second end, firstside sub-inner liner and a second end, second side sub-inner liner. Thesecond end, first side sub-inner liner may form a suction side outerwall of a downstream portion of a suction side of an airfoil usable in agas turbine engine and may include one or more cavities on an inner sideof the suction side outer wall that is configured to form at least aportion of an internal airfoil cooling system. The second end, secondside sub-inner liner may form a pressure side outer wall of a pressureside of the downstream portion of an airfoil usable in a gas turbineengine and may include one or more cavities on an inner side of thepressure side outer wall that is configured to form at least a portionof an internal airfoil cooling system.

A method of forming a turbine component is disclosed. The method mayinclude injecting a ceramic material into at least one inner cavityformed within a composite die cast system, wherein the die cast systemmay be formed from a die housing having one or more inner chambersforming an insert receiving chamber and one or more inner linerspositioned within the insert receiving chamber of the inner chamber ofthe die housing. The inner liner may have an inner surface definingboundaries useful to form an inner surface of a turbine component. Theinner liner may be formed via a selective laser melting process. Themethod may also include removing the die cast system thereby revealing aceramic core.

The method may include firing the ceramic core, placing the ceramic corewithin an inner cavity formed by an inner surface of a wax die, andinjecting wax into one or more openings formed between the ceramic coreand the inner surface of the wax die. The method may also includeremoving the wax die to reveal a wax component, coating the waxcomponent with a ceramic coating to form a ceramic shell with a ceramiccore positioned therein and removing the wax component within theceramic coating leaving one or more cavities within the ceramic coating.The method may also include filling the cavity within the ceramiccoating with a molten metal and removing the ceramic shell and theceramic core to form a cast component.

An advantage of the composite die cast system is that because the innerliner insert only need be removed and replaced to change theconfiguration of an inner surface of a component produced by the system,a significant cost savings is captured in contrast with conventionalsystems in which the die would have to be reworked.

Another advantage of the hybrid die cast system is that use of thehybrid die cast system will reduce time and effort required to create acore die in a conventional casting process.

Yet another advantage of the hybrid die cast system is that the innerliner may be formed from different portions formed from differentmaterials, thereby enabling portions of the inner liner proximate toaspects of the core where intricate aspects of an internal coolingsystem are located, to be formed from more compliant material enablingthose intricate aspects of the internal cooling system to be formed.

These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate embodiments of the presently disclosedinvention and, together with the description, disclose the principles ofthe invention.

FIG. 1 is a perspective view of a conventionally formed core.

FIG. 2 is a cross-sectional view of two adjacent conventional turbineairfoils.

FIG. 3 is a cross-sectional view of a conventional turbine airfoil withan internal cooling system.

FIG. 4 is a cross-sectional view of an inner liner of the die castsystem.

FIG. 5 is a cross-sectional view of an inner liner positioned within adie housing of the die cast system.

FIG. 6 is a cross-sectional view of a ceramic material injected withinthe inner liner positioned within a die housing of the die cast system.

FIG. 7 is a cross-sectional view of a ceramic core.

FIG. 8 is a cross-sectional view of a ceramic core after firing.

FIG. 9 is a cross-sectional view of a ceramic core after firing placedin a wax die and wax injected into the openings between the ceramic coreand the wax die.

FIG. 10 is a cross-sectional view of a wax pattern with the ceramic coreand with the wax die removed.

FIG. 11 is a cross-sectional view of the wax pattern with a ceramicshell formed around the wax pattern.

FIG. 12 is a cross-sectional view of the ceramic shell and ceramic corewith the wax pattern removed.

FIG. 13 is a cross-sectional view of the ceramic shell and ceramic corewith molten metal in the ceramic casting mold.

FIG. 14 is a casting of a component with the ceramic shell and ceramiccore removed.

FIG. 15 is a flow chart of a method of forming a casting component, suchas, but not limited to, an airfoil from cast metal.

FIG. 16 is a cross-sectional view of an alternative inner liner of thedie cast system.

FIG. 17 is a cross-sectional view of the alternative inner liner of FIG.16 positioned within a die housing of the die cast system.

FIG. 18 is a cross-sectional view of a ceramic material injected withinthe alternative inner liner of FIG. 16 positioned within a die housingof the die cast system.

FIG. 19 is a cross-sectional view of a ceramic core.

FIG. 20 is a cross-sectional view of a ceramic core after firing.

FIG. 21 is a cross-sectional view of a ceramic core after firing placedin a wax die and wax injected into the openings between the ceramic coreand the wax die.

FIG. 22 is a cross-sectional view of a wax pattern with the ceramic coreand with the wax die removed.

FIG. 23 is a cross-sectional view of the wax pattern with a ceramicshell formed around the wax pattern.

FIG. 24 is a cross-sectional view of the ceramic shell and ceramic corewith the wax pattern removed.

FIG. 25 is a cross-sectional view of the ceramic shell and ceramic corewith molten metal in the ceramic casting mold.

FIG. 26 is a casting of a component with the ceramic shell and ceramiccore removed.

FIG. 27 is a perspective view of a turbine airfoil formed with the diecast system of FIGS. 4-14 and 16-26 and via the method of using thesystem shown in FIG. 15.

FIG. 28 is a cross-sectional view of the turbine airfoil taken alongsection line 28-28 in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 4-28, a die cast system 10 having an inner linerinsert 12 that enables the configuration of a component 14 produced bythe system 10 to be easily changed by changing the inner liner insert 12without having to rework the die housing 16 is disclosed. Because theinner liner insert 12 only need be removed and replaced to change theconfiguration of an inner surface 18 of a component 14 produced by thesystem 10, the cost savings is significant in contrast with conventionalsystems in which the die would have to be reworked. The die cast system10 may also include an inner liner 12 formed from first and second endsub-inner liners 20, 22, whereby the first end sub-inner liner 20 may befrom a first material that is less compliant than a material forming thesecond end sub-inner liner 22 enabling more intricate cooling systems tobe created by the second end sub-inner liner 22, which is more compliantthan the first end inner liner 20.

In at least one embodiment, the die cast system 10 may include a diehousing 16 may have one or more inner chambers 23 forming an insertreceiving chamber 24. The die cast system 10 may also include one ormore inner liners 12 positioned within the insert receiving chamber 24of the inner chamber 24 of the die housing 16. The inner liner 12 mayhave an inner surface 26 defining boundaries useful to form an innersurface 18 of a turbine component 14. In at least one embodiment, theinner surface 26 of the inner liner 12 may be configured to form anairfoil 138 usable in a gas turbine engine. The airfoil 138 may beformed from a generally elongated, hollow airfoil 140 having a leadingedge 142 on an opposite side from a trailing edge 144 and separated by aconcave pressure side 146 and a convex suction side 148. The generallyelongated, hollow airfoil 60 may have one or more film cooling holes 150at one or more of the leading edge 142 forming a showerhead, concavepressure side 146, the convex suction side 148 or the trailing edge 144,or any combination thereof.

In at least one embodiment, the inner liner 12 may be formed via aselective laser melting process, with a material such as, but notlimited to, iron. The inner liner 12 may be formed from a first sidesub-inner liner 30 forming a first side 32 of the turbine component 14and a second side sub-inner liner 34 forming a second side 36 of theturbine component 14. In at least one embodiment, as shown in FIG. 4-6,the first side sub-inner liner 30 may be formed from an outer wall 38 ofa suction side 40 of an airfoil shaped core 42 and may include one ormore cavities 44 on an inner side 46 of the outer wall 38 that isconfigured to form at least a portion of an internal airfoil coolingsystem 48. The second side sub-inner liner 34 may form an outer wall 50of a pressure side 52 of the airfoil shaped core 42 and may include oneor more cavities 44 on an inner side 56 of the outer wall 50 that isconfigured to form at least a portion of an internal airfoil coolingsystem 48. In at least one embodiment, as shown in FIGS. 4-6, the firstside sub-inner liner 30 and the second side sub-inner liner 34 maytogether form a plurality of inner cavities 44 forming the internalairfoil cooling system 48.

In at least one embodiment, the inner liner 12 may be formed from anon-ceramic material, such as, but not limited to, iron, or anotherappropriate material. The inner liner 12 may be formed from a differentmaterial than the die housing 16. The die housing 16 may be formed froma first sub-die housing 58 and a second sub-die housing 60 having amateable interface 62 positioned therebetween such that the first andsecond sub-die housings 58, 60 are mateable at the mateable interface62.

In at least one embodiment, as shown in FIGS. 16-18, the inner liner 12may be formed from a first end sub-inner liner 20 forming a first end 64of the turbine component 14 and a second end sub-inner liner 22 forminga second end 66 of the turbine component 14. The first end sub-innerliner 20 may be formed from a first material that is less compliant thana material forming the second end sub-inner liner 22. As such, that lesscompliant material may be used to form intricate aspects of the internalcooling system 48. In at least one embodiment, the second end sub-innerliner 22 form from the less compliant material may be formed byprocesses employed by Mikro Systems of Charlottesville, VA. The firstend sub-inner liner 20 may be configured to form a leading edge 70 of anairfoil shaped core 42 usable in a turbine engine, and second endsub-inner liner 22 may be configured to form a trailing edge 72 of theairfoil shaped core 42 usable in the turbine engine.

In at least one embodiment, as shown in FIGS. 16-18, the first endsub-inner liner 20 may be formed from a first end, first side sub-innerliner 74 and a first end, second side sub-inner liner 76. The first end,first side sub-inner liner 74 may form a suction side outer wall 38 ofan upstream portion 78 of a suction side 40 of an airfoil shaped core42. The first end, first side sub-inner liner 74 may include one or morecavities 44 on an inner side 46 of the suction side outer wall 38 thatis configured to form at least a portion of an internal airfoil coolingsystem 48. The first end, second side sub-inner liner 76 may form apressure side outer wall 50 of a pressure side 52 of the upstreamportion 78 of an airfoil shaped core 42. The first end, second sidesub-inner liner 76 may include one or more cavities 44 on an inner side56 of the pressure side outer wall 50 that is configured to form atleast a portion of the internal airfoil cooling system 48.

Similarly, the second end sub-inner liner 22 may be formed from a secondend, first side sub-inner liner 80 and a second end, second sidesub-inner liner 82. The second end, first side sub-inner liner 80 mayform a suction side outer wall 38 of a downstream portion 84 of asuction side 40 of an airfoil shaped core 42 and may include one or morecavities 44 on an inner side 46 of the suction side outer wall 38 thatis configured to form at least a portion of an internal airfoil coolingsystem 48. The second end, second side sub-inner liner 82 may form apressure side outer wall 50 of a pressure side 52 of the downstreamportion 84 of the airfoil shaped core 42 and may include one or morecavities 44 on an inner side 56 of the pressure side outer wall 50 thatis configured to form at least a portion of the internal airfoil coolingsystem 48.

As shown in FIG. 15, a method 100 of forming a turbine component 14 mayinclude forming a ceramic core die 90 at 101 and FIGS. 4 and 16 via aselective laser melting process. The die 90 may be positioned within adie housing 16 at 102 and FIGS. 5 and 17. The method 100 may alsoinclude injecting a ceramic material 98 at 103 and FIGS. 6 and 18 intoone or more inner cavities 44 formed within a die cast system 10 inwhich the die cast system 10 may be formed from a die housing 16 havingone or more inner chambers 23 forming an insert receiving chamber 24.The die cast system 10 may also include one or more inner liners 12positioned within the insert receiving chamber 24 of the inner chamber23 of the die housing 16. The inner liner 12 may have an inner surface26 defining boundaries useful to form an inner surface 18 of a turbinecomponent 14. The inner liner 12 may be formed via a selective lasermelting process. The method may include removing the die cast system 10at 104 and FIGS. 7 and 19 thereby revealing a ceramic core 90.

The method may also include firing the ceramic core 90 at 106 and FIGS.8 and 20 and placing the ceramic core 90 at 108 within an inner cavity92 formed by an inner surface 94 of a wax die 96. The method may alsoinclude injecting wax 88 at 110 and FIGS. 9 and 21 into at least opening92 formed between the ceramic core 90 and the inner surface 94 of thewax die 96. The method may include removing the wax die 96 at 112 andFIGS. 10 and 22 to reveal a wax component 86 and coating the waxcomponent 86 at 114 and FIGS. 11 and 23 with a ceramic coating 116 toform a ceramic shell 118 with a ceramic core 90 positioned therein. Themethod may include removing the wax component 86 at 120 and FIGS. 12 and24 within the ceramic coating 116 leaving one or more cavities 122within the ceramic coating 116. The method may include filling thecavity 122 at 124 and FIGS. 13 and 25 within the ceramic coating 116with a molten metal and removing the ceramic shell 118 and the ceramiccore 90 at 126 and FIGS. 14 and 26 to form a cast component 14.

The step of injection a ceramic material at 102 may include injecting aceramic material into at least one inner cavity 122 formed within thecomposite die cast system 10, wherein the inner liner 12 is formed froma first side sub-inner liner 30 forming a first side 32 of the turbinecomponent 14 and a second side sub-inner liner 34 forming a second side36 of the turbine component 14. The step of injection a ceramic materialat 102 may include injecting a ceramic material into at least one innercavity 122 formed within the composite die cast system 10, wherein thefirst side sub-inner liner 30 may form an outer wall 38 of a suctionside 40 of an airfoil shaped core 42 and may include one or morecavities 44 on an inner side 46 of the outer wall 38 that is configuredto form at least a portion of an internal airfoil cooling system 48. Thesecond side sub-inner liner 34 may form an outer wall 50 of a pressureside 52 of an airfoil shaped core 42 and may include one or morecavities 44 on an inner side 56 of the outer wall 50 that is configuredto form at least a portion of an internal airfoil cooling system 48.

The step of injection a ceramic material at 102 may include injecting aceramic material into at least one inner cavity 122 formed within thecomposite die cast system 10, wherein the inner liner 12 may be formedfrom a first end sub-inner liner 20 forming a first end 64 of theturbine component 14 and a second end sub-inner liner 22 forming asecond end 66 of the turbine component 14, wherein the first endsub-inner liner 20 may be formed from a first material having a lesscompliant than a material forming the second end sub-inner liner 22.

The step of injection a ceramic material at 102 may include injecting aceramic material into at least one inner cavity 122 formed within thecomposite die cast system 10, wherein the first end sub-inner liner 20may be formed from a first end, first side sub-inner liner 74 and afirst end, second side sub-inner liner 76, and wherein the first end,first side sub-inner liner 74 may form a suction side outer wall 38 ofan upstream portion 78 of a suction side 40 of an airfoil shaped core 42and may include one or more cavities 44 on an inner side 46 of thesuction side outer wall 38 that is configured to form at least a portionof an internal airfoil cooling system 48. The first end, second sidesub-inner liner 76 may form a pressure side outer wall 50 of a pressureside 52 of the upstream portion 78 of an airfoil shaped core 42 and mayinclude one or more cavities 44 on an inner side 56 of the pressure sideouter wall 50 that is configured to form at least a portion of aninternal airfoil cooling system 48.

The step of injection a ceramic material at 102 may include injecting aceramic material into at least one inner cavity 122 formed within thecomposite die cast system 10, wherein the second end sub-inner liner 22may be formed from a second end, first side sub-inner liner 80 and asecond end, second side sub-inner liner 82, and wherein the second end,first side sub-inner liner 80 may form a suction side outer wall 38 of adownstream portion 84 of a suction side 40 of an airfoil shaped core 42and may include one or more cavities 44 on an inner side 46 of thesuction side outer wall 38 that is configured to form at least a portionof an internal airfoil cooling system 48. The second end, second sidesub-inner liner 82 may form a pressure side outer wall 50 of a pressureside 52 of the downstream portion 84 of an airfoil shaped core 42 andmay include one or more cavities 44 on an inner side 56 of the pressureside outer wall 50 that is configured to form at least a portion of aninternal airfoil cooling system 48.

The foregoing is provided for purposes of illustrating, explaining, anddescribing embodiments of this invention. Modifications and adaptationsto these embodiments will be apparent to those skilled in the art andmay be made without departing from the scope or spirit of thisinvention.

We claim: 1-13. (canceled)
 14. A core die cast system comprising: a diehousing having an insert receiving chamber; at least one inner linerformed via selective laser melting and positioned within the insertreceiving chamber of the die housing, wherein the at least one innerliner has an inner surface corresponding to an inner surface of aturbine component.
 15. The core die cast system of claim 14,characterized in that the at least one inner liner comprises a firstside sub-inner liner having a body shape corresponding to a first sideof the turbine component and a second side sub-inner liner having a bodyshape corresponding to a second side of the turbine component.
 16. Thecore die cast system of claim 15, characterized in that the first sidesub-inner liner comprises a body shape corresponding to an outer wall ofa suction side of an airfoil in a gas turbine engine, and wherein thesecond side sub-inner liner comprises a body shape corresponding to anouter wall of a pressure side of an airfoil in a gas turbine engine. 17.The core die cast system of claim 14, characterized in that the at leastone inner liner comprises a non-ceramic material.
 18. The core die castsystem of claim 14, characterized in that the at least one inner linercomprises a different material than the die housing.
 19. The core diecast system of claim 14, characterized in that the die housing comprisesa first sub-die housing and a second sub-die housing having a mateableinterface positioned therebetween such that the first and second sub-diehousings are mateable at the mateable interface.
 20. The core die castsystem of claim 14, characterized in that the inner liner comprises afirst end sub-inner liner having a body shape corresponding to a firstend of the turbine component and a second end sub-inner liner having abody shape corresponding to a second end of the turbine component. 21.The core die cast system of claim 20, characterized in that the firstend sub-inner liner comprises a first material less compliant than amaterial of the second end sub-inner liner.
 22. The core die cast systemof claim 20, characterized in that the first end sub-inner linercomprises a body shape corresponding to a leading edge of an airfoil ina turbine engine and second end sub-inner liner comprises a body shapecorresponding to a trailing edge of the airfoil in the turbine engine.23. The core die cast system of claim 20, characterized in that thefirst end sub-inner liner comprises a first end, first side sub-innerliner and a first end, second side sub-inner liner.
 24. The core diecast system of claim 23, characterized in that the first end, first sidesub-inner liner comprises a body shape corresponding to a suction sideouter wall of an upstream portion of a suction side of an airfoil in agas turbine engine and includes at least one cavity defined by the firstend, first side sub-inner liner, and wherein the first end, second sidesub-inner liner comprises a body shape corresponding to a pressure sideouter wall of a pressure side of an upstream portion of an airfoil in agas turbine engine and includes at least one cavity defined by the firstend, second side sub-inner liner.
 25. The core die cast system of claim20, characterized in that the second end sub-inner liner comprises asecond end, first side sub-inner liner and a second end, second sidesub-inner liner.
 26. The core die cast system of claim 25, characterizedin that the second end, first side sub-inner liner comprises a bodyshape corresponding to a suction side outer wall of a downstream portionof a suction side of an airfoil usable in a gas turbine engine andincludes at least one cavity defined by the second end, first sidesub-inner liner, and wherein the second end, second side sub-inner linercomprises a body shape corresponding to a pressure side outer wall of apressure side of the downstream portion of an airfoil in a gas turbineengine and includes at least one cavity defined by the the second end,second side sub-inner liner.
 27. A method of forming a turbine componentcomprising: injecting a ceramic material into at least one inner cavityformed within a core die cast system, wherein the core die cast systemcomprises: a die housing having an insert receiving chamber; at leastone inner liner formed via selective laser melting and positioned withinthe insert receiving chamber of the die housing, wherein the at leastone inner liner has an inner surface corresponding to an inner surfaceof the turbine component; removing the die cast system to reveal one ormore ceramic cores; firing the one or more ceramic cores; placing theone or more ceramic cores within an inner cavity formed by an innersurface of a wax die; and injecting wax into one or more openings formedbetween the one or more ceramic cores and the inner surface of the waxdie; removing the wax die to reveal a wax component; coating the waxcomponent with a ceramic coating to form a ceramic shell with a ceramiccore positioned therein; removing the wax component within the ceramiccoating leaving one or more cavities within the ceramic coating; fillingthe one or more cavities within the ceramic coating with a molten metal;and removing the ceramic shell and the one or more ceramic cores to formthe turbine component with the inner surface.